Police want to know who provided the lethal weapon to a gunman who ran amok in the northwest England and killed 12 people.
Gun laws in the UK are extremely strict and incidents such as these are rare.
A further 25 people were injured after the man opened fire from his car on passers-by.
The violence took place against the background of the scenic Lake District in Cumbria, a well-known tourist destination.
The gunman was Derrick Bird, a 52-year-old divorced father of two. One of his victims is said to have been his twin brother.
Police are trying to establish Bird’s route to discover if there are any more victims.
Detective Chief Constable Stuart Hyde of Cumbria Police said:
“We are not able to understand at this stage the real motivation behind it or establish whether this was a premeditated or a random attack.”
There’s speculation of a blazing row between the family that triggered the violence but neighbours remain surprised at the behaviour of such a quiet man.
“I only saw him the other day, you know. He seemed absolutely fine. Saw him the in the pub a couple of nights ago and he seemed fine then, “said neighbour Derek Ireland.
Bird’s body was found in woods where police believe he turned the gun on himself.
This is the worst multiple shooting in Britain since 1996 when 16 children and their teacher were gunned down in Dunblane, Scotland.